Java後臺使用httpclient入門HttpPost請求（form表單提交，File文件上傳和傳輸Json數據）

一、HttpClient 簡介

HttpClient 是 Apache Jakarta Common 下的子項目，用來提供高效的、最新的、功能豐富的支持 HTTP 協議的客戶端編程工具包，並且它支持 HTTP 協議最新的版本和建議。Java後臺使用httpclient主要目的是爲了模擬客戶端的請求。

2、HttpClient的請求類型

實現了所有的Http請求類型，相應的類爲：HttpGet、HttpPost、HttpDelete、HttpPut

 

3、Http的使用流程

1）導包

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.5</version>
</dependency>
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpmime</artifactId>
    <version>4.5</version>
</dependency>

2）創建連接所需要的配置信息

public class HttpClientConfig {

    static int httpConnectTimeout = 10000;//連接超時時間(單位毫秒)

    static int httpSocketTimeout = 10000;//socket讀寫超時時間(單位毫秒)

    static int httpMaxPoolSize = 100;

    static int httpMonitorInterval = 3000;

    static int httpIdelTimeout = 2000;

    public static int getHttpIdelTimeout() {
        return httpIdelTimeout;
    }

    public static int getHttpSocketTimeout() {
        return httpSocketTimeout;
    }

    public static int getHttpMaxPoolSize() {
        return httpMaxPoolSize;
    }

    public static int getHttpMonitorInterval() {
        return httpMonitorInterval;
    }

    public static int getHttpConnectTimeout() {
        return httpConnectTimeout;
    }
}

3）封裝HttpClientUtils類--包括連接池的信息

public class HttpClientUtils {

    private final static Logger logger = Logger.getLogger(HttpClientUtils.class);
    private static CloseableHttpClient httpClient;
    private static PoolingHttpClientConnectionManager manager; // 連接池管理類
    private static ScheduledExecutorService monitorExecutor; // 監控
    private final static Object syncLock = new Object(); // 相當於線程鎖,用於線程安全
    private static final int CONNECT_TIMEOUT = HttpClientConfig.getHttpConnectTimeout();// 設置連接建立的超時時間爲10s
    private static final int SOCKET_TIMEOUT = HttpClientConfig.getHttpSocketTimeout();
    private static final int MAX_CONN = HttpClientConfig.getHttpMaxPoolSize(); // 最大連接數
    private static final int Max_PRE_ROUTE = HttpClientConfig.getHttpMaxPoolSize();
    private static final int MAX_ROUTE = HttpClientConfig.getHttpMaxPoolSize();

    /**
     * 對http請求進行基本設置
     * 
     * @param httpRequestBase
     *            http請求
     */
    private static void setRequestConfig(HttpRequestBase httpRequestBase) {
        RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(CONNECT_TIMEOUT)
                .setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build();
        httpRequestBase.setConfig(requestConfig);
    }

    public static CloseableHttpClient getHttpClient(String url) {
        String hostName = url.split("/")[2];
        // System.out.println(hostName);
        int port = 80;
        if (hostName.contains(":")) {
            String[] args = hostName.split(":");
            hostName = args[0];
            port = Integer.parseInt(args[1]);
        }
        if (httpClient == null) {
            // 多線程下多個線程同時調用getHttpClient容易導致重複創建httpClient對象的問題,所以加上了同步鎖
            synchronized (syncLock) {
                if (httpClient == null) {
                    httpClient = createHttpClient(hostName, port);
                    // 開啓監控線程,對異常和空閒線程進行關閉
                    monitorExecutor = Executors.newScheduledThreadPool(1);
                    monitorExecutor.scheduleAtFixedRate(new TimerTask() {
                        @Override
                        public void run() {
                            // 關閉異常連接
                            manager.closeExpiredConnections();
                            // 關閉5s空閒的連接
                            manager.closeIdleConnections(HttpClientConfig.getHttpIdelTimeout(), TimeUnit.MILLISECONDS);
                            logger.debug("close expired and idle for over 5s connection");
                        }
                    }, HttpClientConfig.getHttpMonitorInterval(), HttpClientConfig.getHttpMonitorInterval(),
                            TimeUnit.MILLISECONDS);
                }
            }
        }
        return httpClient;
    }

    /**
     * 根據host和port構建httpclient實例
     * 
     * @param host
     *            要訪問的域名
     * @param port
     *            要訪問的端口
     * @return
     */
    public static CloseableHttpClient createHttpClient(String host, int port) {
        ConnectionSocketFactory plainSocketFactory = PlainConnectionSocketFactory.getSocketFactory();
        LayeredConnectionSocketFactory sslSocketFactory = SSLConnectionSocketFactory.getSocketFactory();
        Registry<ConnectionSocketFactory> registry = RegistryBuilder.<ConnectionSocketFactory> create()
                .register("http", plainSocketFactory).register("https", sslSocketFactory).build();
        manager = new PoolingHttpClientConnectionManager(registry);
        // 設置連接參數
        manager.setMaxTotal(MAX_CONN); // 最大連接數
        manager.setDefaultMaxPerRoute(Max_PRE_ROUTE); // 路由最大連接數
        HttpHost httpHost = new HttpHost(host, port);
        manager.setMaxPerRoute(new HttpRoute(httpHost), MAX_ROUTE);
        // 請求失敗時,進行請求重試
        HttpRequestRetryHandler handler = new HttpRequestRetryHandler() {
            @Override
            public boolean retryRequest(IOException e, int i, HttpContext httpContext) {
                if (i > 3) {
                    // 重試超過3次,放棄請求
                    logger.error("retry has more than 3 time, give up request");
                    return false;
                }
                if (e instanceof NoHttpResponseException) {
                    // 服務器沒有響應,可能是服務器斷開了連接,應該重試
                    logger.error("receive no response from server, retry");
                    return true;
                }
                if (e instanceof SSLHandshakeException) {
                    // SSL握手異常
                    logger.error("SSL hand shake exception");
                    return false;
                }
                if (e instanceof InterruptedIOException) {
                    // 超時
                    logger.error("InterruptedIOException");
                    return false;
                }
                if (e instanceof UnknownHostException) {
                    // 服務器不可達
                    logger.error("server host unknown");
                    return false;
                }
                if (e instanceof ConnectTimeoutException) {
                    // 連接超時
                    logger.error("Connection Time out");
                    return false;
                }
                if (e instanceof SSLException) {
                    logger.error("SSLException");
                    return false;
                }
                HttpClientContext context = HttpClientContext.adapt(httpContext);
                HttpRequest request = context.getRequest();
                if (!(request instanceof HttpEntityEnclosingRequest)) {
                    // 如果請求不是關閉連接的請求
                    return true;
                }
                return false;
            }
        };
        CloseableHttpClient client = HttpClients.custom().setConnectionManager(manager).setRetryHandler(handler)
                .build();
        return client;
    }

    /**
     * 關閉連接池
     */
    public static void closeConnectionPool() {
        try {
            httpClient.close();
            manager.close();
            monitorExecutor.shutdown();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

/**
     * 對http請求進行基本設置
     * 
     * @param httpRequestBase
     *            http請求
     */
    private static void setRequestConfig(HttpRequestBase httpRequestBase) {
        RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(CONNECT_TIMEOUT)
                .setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build();
        httpRequestBase.setConfig(requestConfig);
    }

 

4）form表單提交

    public static String doPostForm(String url, Map<String, String> params) {
        HttpPost httpPost = new HttpPost(url);
        setRequestConfig(httpPost);
        String resultString = "";
        CloseableHttpResponse response = null;
        try {

            MultipartEntityBuilder builder = MultipartEntityBuilder.create();

            if (params != null) {
                for (String key : params.keySet()) {
                    builder.addPart(key,
                            new StringBody(params.get(key), ContentType.create("text/plain", Consts.UTF_8)));
                }
            }

            HttpEntity reqEntity = builder.build();
            httpPost.setEntity(reqEntity);

            // 發起請求 並返回請求的響應
            response = getHttpClient(url).execute(httpPost, HttpClientContext.create());
            resultString = EntityUtils.toString(response.getEntity(), "utf-8");

        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (response != null)
                    response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return resultString;
    }

5）File文件上傳

    public static String uploadFile(String url, String localFile, String fileParamName, Map<String, String> params) {
        HttpPost httpPost = new HttpPost(url);
        setRequestConfig(httpPost);
        String resultString = "";
        CloseableHttpResponse response = null;
        try {
            // 把文件轉換成流對象FileBody
            FileBody bin = new FileBody(new File(localFile));

            MultipartEntityBuilder builder = MultipartEntityBuilder.create();

            // 相當於<input type="file" name="file"/>
            builder.addPart("files", bin);
            // 相當於<input type="text" name="userName" value=userName>
            builder.addPart("filesFileName",
                    new StringBody(fileParamName, ContentType.create("text/plain", Consts.UTF_8)));
            if (params != null) {
                for (String key : params.keySet()) {
                    builder.addPart(key,
                            new StringBody(params.get(key), ContentType.create("text/plain", Consts.UTF_8)));
                }
            }

            HttpEntity reqEntity = builder.build();
            httpPost.setEntity(reqEntity);

            // 發起請求 並返回請求的響應
            response = getHttpClient(url).execute(httpPost, HttpClientContext.create());
            resultString = EntityUtils.toString(response.getEntity(), "utf-8");

        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (response != null)
                    response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return resultString;
    }

6) 傳輸Json數據

    public static String doPostJson(String url, String json) {
        HttpPost httpPost = new HttpPost(url);
        setRequestConfig(httpPost);
        String resultString = "";
        CloseableHttpResponse response = null;
        try {
            // 設置ContentType(注:如果只是傳普通參數的話,ContentType不一定非要用application/json)
            // httpPost.setHeader("Content-Type",
            // "application/json;charset=utf8");
            httpPost.setHeader("Content-Type", "application/json");

            // 創建請求內容
            StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON);
            httpPost.setEntity(entity);
            // 執行http請求
            response = getHttpClient(url).execute(httpPost, HttpClientContext.create());
            resultString = EntityUtils.toString(response.getEntity(), "utf-8");
        } catch (Exception e) {
            logger.error("httpclient的get請求失敗,url:" + url, e);
            // e.printStackTrace();
        } finally {
            try {
                if (response != null)
                    response.close();
            } catch (IOException e) {
                logger.error("IOException的錯誤", e);
                // e.printStackTrace();
            }
        }
        return resultString;
    }

 

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